1. Field of the Invention
This invention concerns a new method for making hydrogen peroxide by the acid-catalyzed decomposition of certain dihydroanthracene hydroperoxides. This new reaction provides a method for producing hydrogen peroxide by a three-step process in which hydrogen and oxygen are the only materials ultimately consumed.
Hydrogen peroxide is a valuable industrial chemical. Demand for this chemical in the United States in 1975 has been estimated at 72,000 tons (144,000,000 pounds). The compound is used for bleaching natural fibers and blends of natural fibers with synthetic fibers, for bleaching pulp and paper, for making plasticizers and other chemicals such as organic peroxides, amine oxides, epoxides and glycerol, for treating water, and for etching transistors and other electronic components.
2. Relation to the Prior Art
Hydrogen peroxide is presently prepared commercially by processes involving oxidation of hydrocarbyl-substituted anthrahydroquinones to the corresponding anthraquinones and hydrogen peroxide, followed by catalytic hydrogenation of the quinones back to the hydroquinones. References relating to such processes are summarized in U.S. Pat. No. 3,998,937.
The acid-catalyzed decomposition of cyclic organic hydroperoxides to give hydroxyl compounds and aldehydes or ketones is known. See, for example, Swern, "Organic Peroxides," Vo. II, pp. 65-69 (Wiley; 1971). When the hydroperoxy group is bonded to a nuclear carbon of a tetrahydronaphthlene nucleus, the fused-ring structure of the compound causes the hydroxyl and carbonyl functions to be present in the same molecule following acid-catalyzed decomposition. For example, 1,2,3,4-tetrahydro-1-hydroperoxynaphthlene (equivalent, 1,2,3,4-tetrahydronaphthyl 1-hydroperoxide) and the corresponding 1,4-dimethyl derivative react as follows: ##STR1##
Hydrogenation of anthracene and of alkyl-substituted anthracenes is a known reaction. It can be carried out in the presence of any of a number of catalysts. See for example Garlock and Mosettig, J. Am. Chem. Soc., 67, 2255 (1945). A particularly good catalyst is barium-promoted copper chromite, which is commercially available.
The oxidation of 9,10-dihydroanthracenes to give the corresponding 9-hydroperoxides is also known. See for example Bickel and Kooyman, J. Chem. Soc., 2215 (1956). This reaction is carried out by treating the 9,10-dihydroanthracene with gaseous oxygen in the presence of a free-radical initiator at a temperature in the decomposition range of the initiator. The hydroperoxide can be isolated by conventional methods, either pure or in crude form, usually as a mixture with the corresponding anthracene compound.
The base-catalyzed autoxidation of 9,10-dihydroanthracene to anthraquinone and anthracene is also known. See Hawthorne, et al., ACS Advan. Chem. Ser., 75, 203-215 (1968). Therein, hydrogen peroxide was recovered under basic conditions (p. 214). Under acidic conditions, no recovery of hydrogen peroxide was indicated (p. 209).